Augustine Report Commentary

The Orion was originally intended to hold six people and originally it was larger than it is now. It was downsized several years ago.

The Orion mass was one of the reasons given for requiring the SRB derived Ares booster. Delta and Atlas would not have the required capacity.

Currently the Orion is 16.5 ft in diameter and has a pressurized volume of about 500 cub ft. The Orion will weigh about 19000 lb.

The Apollo CM had a diameter of under 13 ft and a pressurized volume of about 200 cub ft. Apollo normally carried 3, but for rescue and logistics missions could be configured to carry 5 or 6 people. It was configured for 5 for the Skylab and ASTP rescue missions. The Apollo CM weighed about 11000 lb at landing.

About 6 months ago the Program reduced the crew complement on Orion to only 4, indicating this was done because it saved them integration planning work. Some people questioned this. Shuttles have carried anything from 2 to 8 people, and there is a fairly standard checklist for what and how much mass goes with each crew member.

When people questioned whether such a significant change as downsizing the crew might be due to launch mass constraints, the program said the real mass constraint was not launch, but was the Orion landing mass, and that they were at the maximum landing mass with the parachutes they were using, and there was no room for additional or larger parachutes.

Apollo required 2 parachutes for a successful landing. A third was added for redundancy. One chute was lost on Apollo 15 and another nearly lost on ASTP. On A15 one chute collapsed after fuel contaminated the shroud lines, and on ASTP a fuel dump performed out of sequence could have collapsed the shroud lines but did not. (the fuel was sucked into the cabin through the fresh air inlet and did burn the astronauts lungs)

Mass was the reason that the deployable heatshield and aft airbags were deleted from the Orion design, and why the program has ruled out land landings.

Orion has just passed PDR, and weight growth on virtually all aerospace projects lead to expectations that Orion mass will grow through the CDR process and even more as the final flight vehicles are constructed. Mass growth can be predicted based on vehicle size and complexity.

By comparison, Shuttle Orbiter grew from about 151000 lb, its original pre-PDR design mass. By the time the Orbiter structure and landing gear reached CDR, the design mass was 175,000. Actual Orbiter initial Columbia flight mass, was about 220000 lb. Later Orbiters were lighter. 105 was about 192000 lb. (these are launch masses; normal landing masses of just the Orbiter, without payload are about 15000-20000 lb less)

Some have stated concerns that if Orion is at its max mass now, what are they going to do if the mass goes up by 20% - 40%.

Augustine's report said that for a four person crew, a smaller lighter capsule might be considered and desirable, but that this would add at least another year to the already extended development schedule.